The staging of a "type of mock execution of a foreign democratically-elected leader" was "extremely serious", Ulf Kristersson told broadcaster TV4.

Turkey summoned Sweden's ambassador in Ankara on Thursday after the Kurdish Rojava Committee of Sweden compared Erdogan to Italy's late dictator Benito Mussolini.

The Fascist ruler was hung upside down after his execution in the closing days of World War II.

"History shows how dictators end up," the group wrote on Twitter, accompanied by a video showing pictures of Mussolini's 1945 execution and then a dummy painted to look like Erdogan swinging on a rope outside Stockholm's City Hall.

Kristersson said the stunt was even more serious given that Sweden has seen two of its leading politicians assassinated.

Then-prime minister Olof Palme was shot and killed in 1986 and Swedish foreign minister Anna Lindh was fatally stabbed in 2003.

Kristersson said the group's move was intended as "sabotage against Sweden's NATO application."

"It is dangerous for Sweden's security to act in this way," he added.

The incendiary tweet came as Turkey piles pressure on Sweden and fellow NATO hopeful Finland to clamp down on Kurdish groups it views as "terrorists".

Sweden has a larger Kurdish diaspora and a bigger dispute with Turkey.

Ankara has dug in its heels during protracted negotiations that hinge on the extent to which Sweden is ready to meet Turkey's demand to extradite Kurdish suspects and prosecute groups such as the Rojava Committee.